Question

A person driving a car with speed 72km /hr sees a boy crossindlg the road if the distance moved by car before the person applies brakes is 5m the reaction time is

Answer 1

Given speed  = 72km/hr = 72000 m/60 * 60

                                         = 20 m/s

Given distance = 5m

We know that speed = distance/time i.e time = distance/speed
        
                                                                            = 5/20 
                                                                   
                                                                            = 0.25 seconds.



Hope this helps!

Answer 2

72km/h=20m/s

The car covered 5 m in
time=distance/speed
time= 5/20
0.25sec

Hence the reaction time of the person is 0.25seconds.


Got it ......